Electric switch



Oct. 10, 1933. c. HATAY 1,930,093

ELECTRIC SWITCH Filed Jan. 7. 1932 BY MM ATTORNEY Patented Oct. 10, 1933 PATENT OFFICE ELECTRIC SWITCH Charles Hatay, Berlin-Charlottenburg, Germany,

assignor to General Electric Company, a corporation of New York Application January 7, 1932, Serial No. 585,331,

\ and in Germany January 15, 1931 2 Claims.

The present invention relates to electric v switches, and particularly to mercury switches of large current capacity.

A particular object of the invention is to provide a mercury switch capable of interrupting a circuit several hundred times per minute. Another object of the invention is to provide a mercury switch oi relatively large current capacity. Other objects and advantages of my invention will appear. from the following detailed description thereof, or from an inspection of the accompanying drawing.

'The invention consists in a mercury switch having the novel features hereinafter set forth and claimed.

A frequency of switch action of lseveral hundred breaks per minute under high load has not been attainable with hitherto known mercury switches, either because of the large mass to be moved or because, owing to the limited rapidity of switch action, the contact travel or gap had to be made so small to obtain the desired frequency of switch action that the arc persisted.

In the present invention, these difficulties are overcome by means of an armature held at one end by means of thin andI resilient leaf springs while the other end has an extension provided with a `contact dipping into the mercury; moreover, contact is made and broken in an atmosphere resisting the formation of arcs. `In. this arrangement the lever arm of the armature is considerably shorter than that of the contact and the contact travel is so great for a small movement of the armature that the arc is prevented from persisting in case it should form against the action of the arc-resisting atmosphere.

For the purpose of illustration a mercury switch embodying my invention is shown in the accompanying drawing, in which Figure l is a longitudinal section through the switch tube;

Figure 2 is a cross-section, along the line 2-2 of Figure l, through the extension and the armature, showing an electromagnet in operative relation to said armature, and

Figure 3 is an end elevation of the armatureholding leaf springs.

The switch tube essentially consists of a glass vessel l partially lled with mercury 'l and of a tubular extension 2 branching off from about the middle of the said vessel and having an appendage 3. A glass tube 4 is fixed to the bottom of the glass vessel 1 and has its open end projecting beyond the level oi' the mercury l which is therefore accommodated in two concentric spaces to prevent the surface of mercury from quivering when contact action is rapid. Said tube also prevents the arc of rupture from moving into Contact with the sealed vessel. The lower portion of the wall of the tube 4 has apertures 5 through which mercury is allowed to now. The lead 6 ends within the lower portion of the said tube 4. The upper portion of the glass vessel 1 forms a comparatively large condensation chamber. A suitable arc-resisting atmosphere, such as hydrogen, is sealed within the glass vessel 1.

The extension 2 is so inclined relatively to the horizontal that when the switch is in operation the drops of condensed mercury roll back to the vessel 1. The extension 2 accommodates an armature 8 occupying practically the whole length of the said extension and having a double- T cross-section (Figure 2)' with arcuate anges closely bearing on the wall of the extension. One end of the armature 8 has an arm 9 carrying a contact pin 10 of high-melting material such as, for example, tungsten. The other end of the said armature is connected to the, supply of current through the medium of leaf springs 11.

The circuitl within the tube runs from the electrode 6 through the mercury 7, the contact pin 10, the armature 8 and the two leaf springs 11 to the electrode l2. The leaf springs are immersed in mercury 13 in order to prevent undue heating thereof by the current owing through the said springs. The mercury thus takes part in the conduction of current, and also increases the heat conduction from said springs.

The contact within the tube is closed when the mercury switch illustrated'is in its position of rest, in which case the switch may be operated, for example, by means of an electromagnet 14 disposed above the armature 8 as shown in Fig. 2. Current impulses may be applied to the coil of the said electro-magnet; or this coil may be in series with the apparatus to be controlled when the switch tube is to work as a quick-acting switch and at a high rate of contact action so that the mercury switch operates as an automatic circuit-breaker or flasher.

The switch may of course be so vdesigned that the contact within the tube is open when in its position of rest and so that contact is made by operating an electro-magnet disposed under the armature 8.' As in the preceding case, the switch may be operated by means of current impulses applied to the coil, or by self-energization, for which the coil and the switch tube are in paral lel.

When the mercury switch is in operation, the

- material of the contact does not become unduly heated. Moreover, the neutral arc suppressing gas'within the tube not only assists in conveying the heat to the outside but prevents the mercury from undergoing any chemical change.

The travel of the Contact pin 10 may` be a1- tered within certain limits by raising or lowering the level of the mercury in the vessel 1; this is effected by inclining the switch tube and causing mercury to ow from the container 3 to the container 1, or conversely.

What I claim as new and desire to secure by Letters Patent of the United States is:-

1. A mercury switch comprising a sealed envelope having inleads sealed therein, one of said inleads terminating in a pool of mercury, an armature connected to another inlead through. a resilient conductor, said conductor being immersed in another pool of mercury, and a contact carried by said armature, said contact being mov# able into and out of said rst mentioned pool of mercury by movement of said armature.

2. A mercury switch comprising a sealed envelope, a mercury pool in said envelope, a tubular member of vitreous material in said pool with its upper end terminating a short distance above the surface of said mercury, ksaid member having an opening through the wall thereof below the surface of said mercury, an inlead sealed into said mercury pool, another inlead sealed into another part of said envelope, the latter inlead having a contact connected thereto which is adapted to be moved into and out of the mercury Within said tubular member.

CHARLES HATAY. 

